Respirator filter



Jan. 28, 1941. H. s. COVER RESPIRATOR FILTER Filed April 24, 1959 3 Sheets-Sheet 1 Jan. 28, H. s. covER l 2,229,838y

RESPIRATOR FILTER 3 Sheets-Sheet 2 Jan. 28, 1941, H. s. CovER 2,229,838

-RESPIRAI'OR FILTER Filed April 24, 1939 3 Sheets-Sheet 3 @Il 5,23

Patented Jan. 28, 1941 RESPIRATOR FILTER Harvey S. Cover, South Bend, Ind.

Application April 24, 1939, Serial No. 269,643

8 Claims.

My invention relates to improvements in respirators and more specically relates to filter means for respirators and means for attaching filters to respirators and methods of making lilters and, in general, has vfor its objects the production of an improved device to be used in protecting the user from dust, smoke and noxious gases of various kinds. A specific object is the provision of an improved filter bag or box for attachment to a respirator face piece such as shown in my Patent No. 2,120,231.

I have provided a iilter bag or box which may be made from a blank which may be made rectangular in form and entirely of a fabric such as felt. The bag may have, as is well known in the art, a wool felt outer face and a cotton felt inner face. By making the bag or box out of rectangular blanks, there is the advantage that waste of material is eliminated as practically all the material may be utilized, whereas if the blanks were circular, manifestly more of the material would be wasted. Furthermore, I have produced a bag or box which brings about a great saving in labor. By the method of my invention, the blank may be folded across its width so that the folds provide or form one of the sides of the bag or box and no sewing operation is necessary on the folded side.

As will appear hereinafter according to the means and method of my inventions, there is a further advantage in labor saving in that the blanks or bag may be sewn along two adjacent sides in one uninterrupted operation.

The usual opening of the filter element according to the principle of my invention is located at one corner so that by beginning at the folded corner nearest the opening and sewing two sides at once leaves one side remaining unsewn through which the bag can be turned inside out and then this last side may be sewn closed.

Further, according to the method of my invention, the blank with the folded and sewn sides may be turned inside out and this results in the advantage in that the inside seams cause the walls of the filter element to be separated without the use of any spacing elements.

Furthermore, another advantage resides in the fact that no binding is necessary for the edges of the fabric or flexible filter element.

When the bag or box is turned inside out the seams and folds tend to keep the sides of the iilter element apart without the aid of any spacing element whatever. Three sides are always flexed and remain apart. As a result, the filter element not only has a practically one hundred (Cl. ISB-'51) percent filtering area; but Vthe flow of air-is uninterrupted. Furthermore, the lter. element-itself involves the use of no metal parts; The device of my invention also involves novel and improved attaching means for attaching the iilter element -to the respirator whichmeansare releasable and may be operatedvfromthe outside by iiexing the fabric. A still further object `vis the provision of a filter element of the character described which may easily be handledby the inexperienced user and one which is capable ofquick and easy replacement. Y 4 A still further object amongothers isthe'provision of the device of thecharacter described whichis easy of assembly and applicatior'rand which is relatively inexpensive incosty-o'f manu: facture in addition to its high eiciency. Other objects and advantages will be more apparent hereinafter. My invention may be best understoodbyfreff erence to the accompanying drawingsgin which;

Fig. 1 is a front elevation of va respirator with filters attached embodying the principleof-my invention;

Fig. 2 is a side elevation of the same;

Fig. 3 is a horizontal section on the ofFig.2; .f

Fig, 4 is an elevation of one of the filterv elements shown in Fig. 1 showing theside which-is adjacent the body portion;

Fig. 5 is a vertical section on Fig.3;

Fig. 6 is a view substantially similar to that of Fig. 3 showing some of the parts disassembledfwith the lower portion of the iigure in elevation.: i f Fig. 7 is a plan view of one'of the blanks from which the right hand filter element may be made showing the wool side as distinguished fromrI the cotton side; Y e

Fig. 8 is a plan View of one ofthe blanksfroni which the left hand filter element may be made showing the wool side; f

Fig. 9 is a plan View of the washer; f Fig. 10 is a plan view of the elements of' Figs.

the uas-p5 ,of

8 and 9 assembled, the washer preferably` being attached in position on the wool side;

Fig. 11 is a side view ofthe parts shown-'in Fg. 10; Fig. 12 is a plan view of the left'lt'er element showing the plain side of the filter element; that is, theside without a circular opening;

Fig. 13 is a section view of the iilter element of Fig. 12 taken on the line I3-l3 o'f Fig. 12;"

Fig. 14 is a reverse view of the view "shown in Fig. 12 showing the wall of the iilter element having a circular opening;

Fig. 15 is an elevation of the left hand lter element as shown in Figs. 12 to 14, the lter element having been turned inside out and being sewed on the edge 5| ready to be applied to the body portion;

Fig. 16 is a similar view of the right hand filter element;

Fig. 17 is a View of the clamping ring after having been stamped out and before the clamping lugs are bent to form;

Fig. 18 is a view of the clamping ring with the clamping lugs bent at right angles to the ring;

Fig. 19 is a section on the line |9| 9 of Fig. 18;

Fig. 20 is a plan view of the threaded ange rmg; Y

Fig. 21 is a section on the line 2 |-2 I of Fig. 20;

Fig. 22 is a reverse view of that of Fig. 20;v Y

Fig. 2 3 is a; plan view of the clamping ring assembled with the threaded ange ring;

Fig. 24 is an elevation of the same. y

The preferred form of my invention which has been selected to illustrate the principle of said invention includes a respirator body 25 provided with cut-outs 26 to accommodate the nose of the wearer. The cut-outs 26 are particularly shown in Figs. 3, 5 and 6. A cut-out is provided at the top and bottom of the respirator 25 which makes it possible to invert the body.

The body 25 is provided with a bulbous valve housing 21 having exhaust epenings 28 as shown in Figs. 3, 5 and 6. In the form shown it will be noted that one of the openings is superimposed over the other. Located in the housing 21 is a valve seat 29 which in the form shown is oval and is provided with a flange 30. The valve seat 29 is retained in place as shown in Figs. 3, 5 and 6j by an inner retaining shoulder 3|, and outer retaining shoulders 32 as shown in said gures.

' The seat 29 is concaved as at 33 and is provided with valve openings 34. The valve seat 29 is preferably provided around the openings 34 with sharp flared edges 35. By the arrangement of the sharp ared edges 35 with the valve 36 'there is only a minimum of contact between the valve and the valve seat in the valve area and this arrangement of the sharp flared edges has the advantage of eliminating any tendency there might be for the valve to stick or adhere momentarily to the valve seat or to act sluggishly, for example, under unusual atmospheric conditions.

The valve 36 is a flat valve which is oval in form and is attached in the central area of the valve by means of flanged supporting posts 31 as shown in Figs. 3, 5 and 6. By virtue of this arrangement the valve 36 lies against the valve seat with a minimum of contact in the valve opening area. 'I'he valve is normally closed to seal ofl"v tightly the outsidev air. and at the same timer has a sensitive action to meet the needs of expiration. y

The body portion 25, looking at the drawings as shown in Figs. 3 and 6, has an integral right Wall 38 and an integral left wall 39 and the walls 38 and 39 are each provided with openings 40, as shown in Figs. 3, 5 and 6.

Adapted to be secured to each of these walls 38 and 39 in the area of the openings 4U is a filter element. There are two of these lter elements and a description of one of these elements and the means for connecting and supporting it upon the body will suiiice with the exceptions hereinafter noted.

Adapted to fit into one of the openings 48 is a anged threaded locking cap 4| having an opening 42 and a threaded portion 43, clearly illustrated in Fig. 6. The flanged threaded locking cap 4| is adapted to have its threaded portion 43 extend through one of the openings 40 in one of the walls of the body portion and each cap is adapted to be used to lock a lter element to the body portion. Each cap is adapted to be used in combination with one of a pair of lter elements, to-wit, either a right hand filter element 44 or a left hand filter element 45.

As clearly shown in Fig. 7, the right hand filter element may be made from a blank 46 in which the blank is shown with its wool side showing as distinguished from its cotton side. In Fig. 8

fthere is shown a blank 48 from which a left hand lter element may be made. Referring to the right hand blank 46, shown in Fig. 7, there is provided a hole 41 in the upper left hand corner, looking at the drawings, as illustrated in Fig. "i, whereas the blank 48 for the left hand lter element has its hole 49 in the upper right hand corner. These blanks 46 and 48 are preferably made in substantially rectangular form and this, in addition to other advantages, has the advantage of practically eliminating waste of material, as practically all of the felt may be used, whereas if the blanks are made in circular or disk like form it is manifest that there would be great waste of material. In addition, as will be seen, there is also the advantage that by making the blanks rectangular they may be folded and eliminate the .need for sewing one of the sides, thus reducing the labor necessary besides providing a' side of the lter element, which is perfectly efficient for filtering and has other advantages which will vbe more apparent.

Referring to Fig. 8, the blank 48 has straight parallel side edgeslengthwise, 59 and 5|, and straight parallel end edges 52 and 53. The blanks in the form shown are provided preferably with wool surface 54 and cotton surface 55, although it will be understood by those skilled in the art that this may be changed. The blanks 46 and 48 have rounded corners 55.

Preferably washers 51 are used around the openings 41 and 49 in the blanks, the washers having opening 58 to register with the holes in the blanks. The washers may be sewn as at 59 to the blanks as illustrated at Fig. 10, or may be otherwise secured to the blanks or left unattached. The washer is preferably attached eXteriorly of the ltervelernent for convenience so as to lie between the 'filter element and the body portion when in use. Although it is not necessary to employ the washer, the washer has been found highly advantageous in respect of making a convenient air-tight seal.

As shown in Fig. 12, the blank 48 may be doubled in the course of manufacture with the cotton side 55 outside forming a folded edge 68. The edges 58 may then be sewed together as at 6|, and the edges 52 and 53 may be sewed together as at 62, leaving an opening 63, only, between the unsewn edges 5|. 'I'he condition of the lter element in this stage of manufacture is illustrated in Figs. 12 to 14.

In this condition the lter element may be pulled inside out to the condition shown in Fig. l5, the sides 5| may be sewed as at 64. This construction has the advantage that when the lter element is turned inside out, the seams and folds cause the bag to assume ar shape and curvature shown clearly in Figs. 3 and 6, and tend to keep the sides of the bag apart without the aid of a spacing element. Three sides of each iilter element are always flexed so as to cause the filter element to remain bulged out.

As shown in Fig. 17 there is provided a clamping ring 65 having an opening 66 .and it is provided with ring clamping lugs or ears 61 and felt clamping lugs or ears 68. Adapted to be clamped to the clamping ring 65 is a threaded flange ring 69 clearly shown in Figs. 20 to 22 which has an outer face 10 .adapted to have the lugs 61 clamped against it and an inner face 1I adapted to abut the clamping ring 65. The threaded ange ring 69 has a threaded channel flange 12 having an opening 13. As illustrated in Fig. 24 the lugs 61 may be bent against the face 10 to clamp the threaded flange ring 69 against the clamping ring B5. The channel ange is adapted to be inserted through the opening 41 or 49 of the felt, as the case may be, and opening 58 of the washer 59. The felt and washer 59 are adapted to be positioned around the channel flange 12, and under the felt clamping lugs 68 as illustrated in Fig. 4, which shows the body engaging side of the right lter element.

The filter elements are adapted to be united to the body portion by inserting the ange of the anged threaded locking cap 4| through one of the openings 40 of the side walls of the body portion and then into the threaded channel ange 12 and screwing the parts together.

It will be understood that there may be two filter units and a set of clamping elements for each filter unit to connect the filter unit or element to a wall of the body portion of the respirator.

While I have illustrated and described therefor the preferred form of structure and method for carrying my invention into effect, I do not wish to be limited to the details set forth, but desire to avail myself of such variation and modification as come within the scope of the appended claims.

Having thus described my invention, what I claim as `new and desire to claim as Letters Patent is:

1. A filter element of felt like material for a respirator, said filter element having a formation for creating in the filter walls a stress causing the walls to space from each other including a marginal portion doubled inwardly and secured to another marginal portion.

2. A filter element of felt like material for a respirator, said lter element having a formation for creating in the filter walls a stress causing the walls to space from each other, said formation including edges doubled inwardly and secured together.

3. A filter element of felt like material for a respirator, said lter element having a formation for creating in the filter walls a stress causing the walls to space from each other, said formation including adjacent edges on two sides doubled inwardly and sewn together.

4. A filter element of felt like material for a respirator, said lter element having a formation for creating in the filter walls a stress causing the walls to space from each other, said formation including .a fold adapted to form opposing walls and to space the walls from each other, the walls being secured at their opposed marginal portions to form an enclosed air chamber,

5. A filter element of felt like material for a respirator, said iilter element having a formation for creating in the filter walls a stress causing the walls to space from each other, said formation including a folded blank with edges doubled inwardly and secured together.

6. A lter element of felt like material for a respirator, said filter element having a formation for creating in the lter walls a stress causing the walls to space from each other, said formation including a folded blank with adjacent edges on two sides doubled inwardly and sewn together, the remaining edges being sewn together.

7. A filter element of felt like material for a respirator, said filter element having a formation for creating in the filter walls a stress causing the walls to space from each other, said formation including a blank folded on one side, with an inside seam on another side and an outside seam on still another side.

8. A filter element of felt like material for a respirator, said lter having a formation for creating in the iilter walls a stress causing the walls to space from each other, said formation including a peripheral portion of one wall doubled inwardly and secured to the peripheral portion of the opposed wall.

HARVEY S. COVER. 

